Due to the world's increasing population and decreasing amount of arable land, there is a pressing need for methods to increase the productivity of agricultural crops. Given this need to produce increased amounts of food and feed, plants are increasingly being grown in varied locations and/or under climactic conditions in which insect pressure does not exist. For example, more and more crops are being produced in greenhouses or other shelters where insect pressures can be easily minimized. Plants with increased cold and/or drought tolerance are being developed which may eventually permit them to grow under climactic conditions which are inhospitable to their traditional insect pests.